(1) Field of the Invention
The present invention refers to an improved device for the elimination of trims of rolls or logs of sheeted material, in particular which can be associated with a cutting-off machine.
(2) Description of Related Art
In the field of the production of rolls or the like of kitchen and/or toilet paper rolls of paper are realised wound on rods or cores having a predetermined diameter and height. Then, one must proceed to the cutting to size of individual rolls at their final size, also predetermined, which are ready for distribution and end use by the consumer.
It is currently known to cut these end rolls to a predetermined size through suitable cutting-off machines which receive, for example, a series of logs, arranged parallel to each other, and cut them into a plurality of short rolls, which are thus arranged in order one after the other, and they are of the required size.
Such an operation is carried out on cutting-off machines, in general through rotary blades, and has as an end result the formation of a plurality of rolls or slugs of the required size, formed by an elongated log or roll which advances step by step.
During this operation, both in the top end of the individual log or roll and in the bottom end slugs are also realised which cannot be used and are in the form of short little rolls, i.e. not of the required standard measurement. Since the finished rolls fed one after another towards the subsequent packaging, in general, these little rolls or trims deriving from the cutting of the logs must be eliminated during the evacuation of the rolls cut to measure so as not to create obstructions to packaging.
Indeed, it is clear that the presence of end little rolls or trims could even lead to the blockage of the packaging machine, not to mention the possible formation of package with the wrong number of correct and usable rolls, caused by the presence of little rolls or trims.
Precisely to try to eliminate these clear problems, complex devices have been realised and are used which allow the elimination of little rolls or trims.
A first device foresees the sucking up of all of the rolls cut to size as soon as they advance one after another, after cutting. On the other hand, the little rolls or trims, not held by the suction, are sent towards a discharge opening, when the little rolls or upstream trims and downstream trims come directly from the cutting-off machine.
The strict correlation of the elements of these devices determines a machine which is complex to construct and to synchronise. Moreover, a fine tuning of all of the accessory parts necessary both for the suction of the rolls and the transportation thereof must be foreseen. The suction which acts on the outer part of the advancing roll can also determine biting or outer damage of the product, and consequently a not totally optimal finished outer appearance thereof, according to the requirements of the end user.
A second device for the elimination of trims already known and used comprises an opening with which two planes or walls are associated to form a trap door which opens or closes the hole according to predetermined and correlated sequences. All of this takes place according to the cut product passing through be it a roll cut to size or a little roll or trim. Indeed, a first trap-door plane closes the opening, once the upstream trim has passed, and a second trap-door plane intervenes, when arrives the downstream trim, in other words when the passage of rolls cut to the correct size recommences.
This second device, although it functions well, can create problems connected to the movement in perfect synchronisation between the two trap-door planes and the transporters for advancing the rolls and the trims in order. Indeed, there is the possibility of blockage and there are problems of precise and correct fine tuning.